By Jill Barnes Nelson
Tehachapi News
MOJAVE — It's taken more than three-quarters of a century, but gold is finally being produced at Golden Queen Mine.
For the first time since the 1930s, the Golden Queen Mine had its “first pour” of gold about two weeks ago. Gold mined from the facility in an elaborate process — with all types of environmental stipulations — was processed into the first gold ingot. Because of security issues, the exact amount of the mold was not disclosed, according a statement from mine officials.
"The first gold pour is a remarkable milestone signifying the company's transition to a gold producer," Thomas M. Clay, Golden Queen Mining Co. chairman and interim chief executive officer, said in an announcement from the firm's headquarters in British Columbia, Canada. "We are proud of what we have accomplished and are excited to move closer to entering full production as a gold company in California."
Golden Queen Mine, located along Soledad Mountain in Mojave, first produced both gold and silver from the mine before World War II. Mining ceased after the war because of low prices for the precious metals.
When prices began to rise, Golden Queen Mine began a renewed effort to extract the gold. It began applying for permits and began the long process of mining the gold in 2012.
Some 100 employees are employed full-time at the mine, where excavation began last spring and the chemical process to remove gold and silver started in early February. Company officials did not disclose potential production rates but said initial flow rates in what is called the "leach pile" have been very good.
Mining is done a lot differently at Golden Queen than what viewers might see on the show “Gold Rush,” where gold is done with a sluicing method.
Construction on the mine's infrastructure started more than a year ago. Rock ore material that holds gold is crushed and a century-old chemical separation technique called the Merrill-Crowe process is used by which gold and silver is removed from a cyanide solution that trickles through piles of ore. Drilling and blasting is used to free the rock, which is then carried away with front-end loaders and mechanized shovels and loaded into trucks that can carry 100 tons each.
Rocks go through a three-stage crushing process to create progressively smaller pieces of ore, ending up with pieces measuring less than a half-inch. The crushed ore is then stacked on top of the leach pad in piles about 20 to 300 feet high.
In order to provide impermeable barriers between the pad and the ground beneath, a clay liner was built using old tailings from the mine, as well as a layer of plastic. Crushed rock is layered on top of that.
Gold and silver are filtered out of the solution using a process that introduces zinc powder to take the place of the precious metals in the solution. The gold extracted from the solution is then melted and poured into molds to form ingots.